利用线粒体DNA的细胞色素b(cytb)和控制区(D-loop)的部分序列来研究大泷六线鱼4个群体(包括野生和养殖群体)的遗传多样性.PCR扩增后分别得到365 bp(cytb)和387 bp(D-loop)的碱基序列.Mega计算结果显示cytb中A+T的含量(52.6%)高于G+C的含量(47.3%);D-loop中A+T的含量(69.3%)同样高于G+C的含量(30.7%).4个群体平均的变异位点、单倍型数、单倍型多样性、核苷酸多样性及平均核苷酸差异数,cytb基因分别为10,7.75,0.739,0.0073和2.656;D-loop区分别为18.25,12.75,0.846,0.0121和4.673.4个群体的遗传多样性由高到低分别为舟山、大连、琅琊台、即墨养殖群体,养殖群体的多样性低于野生群体.基于野生群体cytb和D-loop的分子变异分析(AMOVA)得出的F st分别为0.3186和0.2714,显示了变异主要发生在群体内部.基于Kimura 2-parameter模型构建的NJ树结果表明3个野生群体间没有显著的分化.线粒体cytb基因和D-loop区均可作为检测大泷六线鱼遗传多样性的有效标记.%Nucleotide sequences of mitochondrial DNA cytb and D-loop from 4 different populations of Hexagrammos otakii were amplified by using PCR technique,365 bp and 387 bp nucleotide sequences were obtained to study the genetic diversity of Hexagrammos otakii .The results showed that the content of A+T (52.6% )was higher than G+C(47.3%)in cytb ,and it was also higher in D-loop (content of A+T and G+C was 69.3%,30.7% respectively)through Mega calculation,the total variable sites,number of haplotypes(h),haplotype diversity(Hd),nucleotide diversity (π)and mean pairwise nucleotide differences (k)of 4 populations were 10,7.75,0.739,0.0073,2.656 based on cytb and 18.25,12.75,0.846,0.0121, 4.673 based on D-loop,respectively.Diversities from high to low were Zhoushan,Dalian,Langyatai and Jimo (cultured population).Diversity in cultured population was lower than that in wild population.F st values were 0.3186 and 0.2714 based on cytb and D-loop of wild populations through analysis of molecular variance (AMOVA)respectively,demonstrating that the variation is mainly within the population.The NJ molecular phylogenetic trees based on Kimura 2-parameter model showed that three different geographic stocks have no apparent geographic subdivision.In short,it suggested that the mitochondrial DNA cytb and D-loop may serve as an effective marker for analysis of genetic diversity of Hexagrammos otakii popula-tions.
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